Hygiene hypothesis and prevalence of glomerulonephritis

Toxic Occupational Exposures and Membranous Nephropathy

BACKGROUND AND OBJECTIVES

Membranous nephropathy is a rare autoimmune kidney disease whose increasing prevalence in industrialized countries pleads for the involvement of an environmental factor in the development of the disease. In addition, the predominance of men in membranous nephropathy, classically attributed to biologic or genetic differences between men and women, could also be due to different occupational exposures. To support this hypothesis, we sought to describe the toxic occupational exposures of patients with membranous nephropathy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this observational epidemiologic study, we compared the occupations and toxic occupational exposures of 100 patients with membranous nephropathy with those of the general population, consisting of two cohorts of 26,734,000 and 26,500 French workers. We then compared the characteristics of patients exposed to an occupational toxic substance with those of unexposed patients.

RESULTS

Patients with membranous nephropathy worked more frequently in the construction sector than the general population (33% versus 7%, P<0.001). This difference remained significant by age and sex. They were also more frequently exposed to toxic substances, such as asbestos (16% versus 5%, P<0.001), lead (9% versus 1%, P<0.001), or organic solvents (37% versus 15%, P<0.001), than the general population. The predominance of men in the subgroup of patients occupationally exposed to toxic substances was not observed in unexposed individuals (organic solvents: 80% men versus 41%, P<0.001; asbestos: 90% men versus 55%, P=0.004). In addition, patients with phospholipase A2 receptor 1 (PLA2R1) epitope spreading were more frequently exposed to asbestos and organic solvents than patients without epitope spreading (32% versus 7%, P=0.02 and 74% versus 43%, P=0.02, respectively), with a dose-dependent effect.

CONCLUSIONS

Patients with membranous nephropathy were more frequently exposed to certain occupational toxic substances, such as asbestos and organic solvents, than the general population. This occupational exposure was more frequent in men and in patients with PLA2R1 epitope spreading.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Immunopathological Analysis in a French National Cohort of Membranous Nephropathy (IHMN), NCT04326218.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_10_25_CJN02930322.mp3.

Educational Attainment Is Associated With Kidney and Cardiovascular Outcomes in CKD

Introduction

Prospective data on impact of educational attainment on prognosis in patients with chronic kidney disease (CKD) are scarce. We investigated the association between educational attainment and all-cause mortality, major adverse cardiovascular (CV) events (MACEs), kidney failure requiring dialysis, and CKD etiology.

Methods

Participants (N = 5095, aged 18–74 years) of the ongoing multicenter German Chronic Kidney Disease (GCKD) cohort, enrolled on the basis of an estimated glomerular filtration rate (eGFR) of 30 to 60 ml/min (stages G3, A1–A3) or overt proteinuria (stages G1–G2, A3), were divided into 3 categories according to their educational attainment and were followed for 6.5 years.

Results

Participants with low educational attainment (vs. high) had a higher risk for mortality (hazard ratio [HR] 1.48, 95% CI: 1.16–1.90), MACE (HR 1.37, 95% CI: 1.02–1.83), and kidney failure (HR 1.54, 95% CI: 1.15–2.05). Mediators between low educational attainment and mortality were smoking, CV disease (CVD) at baseline, low income, higher body mass index, and higher serum levels of CRP, high-density lipoprotein cholesterol, uric acid, NGAL, BAP, NT-proBNP, OPN, H-FABP, and urea. Low educational attainment was positively associated with diabetic nephropathy (odds ratio [OR] 1.65, 95% CI: 1.36–2.0) and CKD subsequent to acute kidney injury (OR 1.56, 95% CI: 1.03–2.35), but negatively associated with IgA nephropathy (OR 0.68, 95% CI: 0.52–0.90).

Conclusion

Low educational attainment is associated with adverse outcomes and CKD etiology. Lifestyle habits and biomarkers mediate associations between low educational attainment and mortality. Recognition of the role of educational attainment and the associated health-relevant risk factors is important to optimize the care of patients with CKD and improve prognosis.

Analysis and Study on Epidemiological Features and Prognosis of Nephrotic Syndrome in Xinjiang and Heilongjiang

Backgrounds

The pathogenesis of nephrotic syndrome (NS) is complex, and there are differences between regions. This study attempted to collect clinicopathological data of patients diagnosed with NS in Xinjiang and Heilongjiang in the past 2 years, so as to explore the onset features of NS and treatment and prognosis of patients in the two regions.

Methods

Clinical data of 375 patients diagnosed with NS using renal biopsy in Xinjiang and Heilongjiang from March 2019 to March 2021 were collected. Clinical data of patients before treatment were collected, and the chi-square test was utilized to compare the differences in the sex distribution of two groups. The U test was utilized to compare abnormal distribution continuous data between two groups, such as age, hemoglobin, plasma albumin, proteinuria, and triglycerides. Independent sample t-test was utilized to compare normal distribution continuous data between two groups, such as serum total protein, serum creatinine, blood urea nitrogen, glomerular filtration rate, and total cholesterol. The independent sample t-test was also used to compare the immunoglobulin levels and complement levels between the two groups after treatment, including IgA, IgG, IgM, C3, and C4. Kaplan-Meier method was used to analyze and plot the cumulative curves of complete remission rate and partial remission rate.

Results

For 275 NS patients from Xinjiang, the male-to-female ratio was 0.81 : 1. For 84 patients from Heilongjiang, the male-to-female ratio was 1.05 : 1. The onset ages of patients in Xinjiang and Heilongjiang were 22-45 years old and 22-47 years old, respectively. Respectively, there were 221 cases (80.36%) and 66 cases (78.57%) of primary NS in Xinjiang and Heilongjiang. There were 54 cases (19.64%) and 18 cases (21.43%) of secondary NS in Xinjiang and Heilongjiang, respectively. There was no statistically significant difference in cause distribution between the two regions (p = 0.756). After treatment, immunoglobulin levels (IgA (p = 0.009), IgG (p = 0.002), IgM (p < 0.001)) and complement C3 (p < 0.001) and C4 (p < 0.001) levels in Xinjiang and Heilongjiang were statistically significant. 129 cases in Xinjiang (46.91%) and 55 cases in Heilongjiang (65.48%) were treated with glucocorticoid (GC) combined with immunosuppressive therapy, respectively. After receiving treatment, 67 (24.36%) of 275 patients in Xinjiang achieved complete remission, 166 (60.36%) achieved partial remission, 22 (26.19%) of 84 patients in Heilongjiang achieved complete remission, and 56 (66.67%) achieved partial remission, and there was no statistically significant difference in remission rate between the two regions (p = 0.159). Patients in Xinjiang and Heilongjiang achieved complete remission at an average of 10.34 weeks (9.98-10.70) and 9.95 weeks (9.26-10.65), respectively. There was no significant difference in complete remission rates between the two regions (p = 0.663). Patients in Xinjiang and Heilongjiang achieved partial remission at an average of 8.76 weeks (8.38-9.14) and 7.99 weeks (7.33-8.65), respectively. There was no significant difference in the partial remission rate between the two regions (p = 0.065).

Conclusion

The causes of NS in Xinjiang and Heilongjiang were similar. After treatment, there were differences in immunoglobulin levels (IgA, IgG, IgM) and complement levels (C3, C4) in the two regions. The main treatment methods used in the two regions were GC combined with immunosuppressive therapy. The prognosis of patients in the two regions was similar. The complete remission rate and partial remission rate after treatment in the two regions were similar, and the average time required to achieve complete remission and partial remission was also similar.

Serum interferon-γ and urinary monocyte chemoattractant peptide-1 are important factors in the pathogenesis of immunoglobulin A nephropathy

Background

Imbalance of T helper (Th) 1/2 cells has been shown to contribute to the development of immunoglobulin A nephropathy (IgAN). To address the inconsistent results on the role of Th1/Th2 polarization, we evaluated the levels of Th1/Th2 cytokines in various samples from patients with IgAN.

Methods

Thirty-one patients with biopsy-proven IgAN (age, 34.48 ± 12.10 years) and 25 healthy controls (age, 44.84 ± 13.72 years) were enrolled. We evaluated the relationship between the levels of Th1/Th2 cytokines and the response to glucocorticoid treatment.

Results

The levels of serum interferon-gamma (IFNγ) and urinary monocyte chemoattractant peptide (MCP)-1 were higher in the IgAN group than in the control group. The levels of MCP-1 in urine and secreted by peripheral blood mononuclear cells (PBMCs) were significantly different among three groups categorized based on daily proteinuria. The level of urinary MCP-1 was significantly correlated with proteinuria. The levels of urinary MCP-1, serum interleukin (IL)-4, IFNγ, and IL-2 secreted by PBMCs and intrarenal IL-1 messenger RNA (mRNA) were significantly correlated with the ratio of proteinuria at 6 months to baseline proteinuria in patients undergoing glucocorticoid treatment. MCP-1 mRNA and protein levels were significantly upregulated in mesangial cells stimulated with IFNγ among representative Th1/Th2 cytokines.

Conclusion

IFNγ was shown to be a key cytokine in the pathogenic processes underlying IgAN, and its upregulation induced an increase in urinary MCP-1 production. These findings suggest that Th1 cytokines may play an important role in the development of IgAN.

Th17-Immune Response in Patients With Membranous Nephropathy Is Associated With Thrombosis and Relapses

Membranous nephropathy (MN) is a rare autoimmune kidney disease. Most autoimmune diseases are associated with a pro-inflammatory Th17-immune response, but little is known about immune dysregulation in MN. In China, MN was associated with exposure to fine air particulate matter (PM_2.5) that could act as a danger signal and redirect immune response toward the Th2 or Th17 pathway. We aimed to analyze the cytokine profile of MN patients and to study the possible environmental factors involved in this immune reorientation, as well as the consequences on the prognosis of the disease. In this prospective study, 59 MN patients filled a comprehensive lifestyle questionnaire. Peripheral blood cells from MN patients were stimulated in vitro to measure the cytokines produced in supernatant. Cytokine profiles of MN patients were compared to 28 healthy donors and analyzed regarding individual PM_2.5 exposure. Compared to healthy donors, MN patients had higher serum levels of Th17 and Th2 cytokines IL-17A (62 pg/ml [IQR, 16–160] versus 31 [IQR, 13–51], P=0.035), IL-6 (66767 pg/ml [IQR, 36860–120978] versus 27979 [IQR, 18672–51499], P=0.001), and IL-4 (12 pg/ml [IQR, 0–33] versus 0 pg/ml [IQR, 0–0], P=0.0003), respectively, as well as a deficiency of Th1 and regulatory T cell cytokines IFN-γ (5320 pg/ml [IQR, 501–14325] versus 18037 [IQR, 4889–31329], P=0.0005) and IL-10 (778 pg/ml [IQR, 340–1247] versus 1102 [IQR, 737–1652], P=0.04), respectively. MN patients with high IL-17A levels lived in areas highly exposed to PM_2.5: 51 μg/m³ versus 31 μg/m³ for patients with low IL-17A levels (P=0.002) while the World Health Organization recommends an exposition below 10 μg/m³. MN patients with Th17-mediated inflammation had more venous thromboembolic events (P=0.03) and relapsed more often (P=0.0006). Rituximab treatment induced Th1 and regulatory T cell cytokines but did not impact Th17 cytokines. MN patients with Th17-mediated inflammation which appears to be related to an urban environment have worse prognosis. Alternative strategies targeting dysregulated cytokine balance could be considered for these patients at high risk of relapse.

Glomerular disease frequencies by race, sex and region: results from the International Kidney Biopsy Survey

Background

Large-scale studies comparing glomerular disease frequencies across continents are lacking.

Methods

We surveyed 29 nephropathology laboratories in four continents using a standardized data collection form. We obtained recent consecutive kidney biopsy diagnosis frequencies at each center and summary demographics for each diagnosis. This report focuses on glomerular disease frequencies by region and race/ethnicity.

Results

Among 42 603 glomerular disease diagnoses reported (median age 47 years, 52% male, 57% white), from a total of 60 340 diagnoses, glomerular disease subtype frequencies differed considerably by continent. Diabetic glomerulosclerosis (GS; 19.1%) and focal segmental glomerulosclerosis (FSGS; 19.1%) predominated in North America; lupus nephritis (38.1%) and FSGS (15.8%) predominated in Latin America; IgA nephropathy (IgAN; 22.1%) and FSGS (14.9%) predominated in Europe; and IgAN (39.5%) and lupus nephritis (16.8%) predominated in Asia. After stratifying by race, diabetic GS (17.4% versus 4.3%, P < 0.001) and FSGS (17.3% versus 11.8%, P < 0.001) were more, and lupus nephritis less (15.8% versus 45.6%, P < 0.001), frequent among Latinos in North versus Latin America; FSGS was more (13.1% versus 7.1%, P < 0.001), and IgAN less (27.4% versus 40.5%, P < 0.001), frequent among Asians in North America versus Asia; and FSGS (18.9% versus 13.5%, P < 0.001) and diabetic GS (18.7% versus 6.5%, P < 0.001) were more, and IgAN less (14.4% versus 25.4%, P < 0.001), frequent among whites in North America versus Europe.

Conclusions

We determined that glomerular disease frequencies differed by continent, even among patients of similar race/ethnicity. Regional environmental and lifestyle factors, and local biopsy policies, might influence glomerular disease epidemiology independently of race/ethnicity.

Patterns of renal disease in South Korea: a 20-year review of a single-center renal biopsy database

Background: Several registries and centers have reported the results of renal biopsies from different parts of the world. As there are few data regarding the epidemiology of glomerulonephritis (GN) in South Korea, we conducted this study on renal biopsy findings during the last 20 years from a single center.

Methods: Data for 818 patients who underwent renal biopsy at our center between 1992 and 2011 were collected retrospectively. All kidney specimens were examined with light microscopy (LM) and immunofluorescent microscopy (IF).

Results: There were 818 cases of native kidney biopsies. In cases of primary GN, the most frequent type of renal pathology in adults (18–59 years) was mesangial proliferative GN (MsPGN, 34.5%) followed by IgA nephropathy (IgAN, 33.3%) and membranous GN (MGN, 8.8%). Indications in adults (18–59 years) were asymptomatic urinary abnormalities (75.3%) followed by nephrotic syndrome (19.8%) and acute kidney injury (AKI, 3.4%).

Conclusions: Among 818 renal biopsy specimens, MsPGN and IgAN were the most frequent biopsy-proven renal diseases. MGN was the third most common cause of primary GN and lupus nephritis (LN) was the most common secondary glomerular disease. Our data contribute to the epidemiology of renal disease in South Korea.

Inhibition of STAT3 Signaling Reduces IgA1 Autoantigen Production in IgA Nephropathy

Introduction

IgA nephropathy is a chronic renal disease characterized by mesangial immunodeposits that contain autoantigen, which is aberrantly glycosylated IgA1 with some hinge-region O-glycans deficient in galactose. Macroscopic hematuria during an upper respiratory tract infection is common among patients with IgA nephropathy, which suggests a connection between inflammation and disease activity. Interleukin-6 (IL-6) is an inflammatory cytokine involved in IgA immune response. We previously showed that IL-6 selectively increases production of galactose-deficient IgA1 in IgA1-secreting cells from patients with IgA nephropathy.

Methods

We characterized IL-6 signaling pathways involved in the overproduction of galactose-deficient IgA1. To understand molecular mechanisms, IL-6 signaling was analyzed by kinomic activity profiling and Western blotting, followed by confirmation assays using siRNA knock-down and small-molecule inhibitors.

Results

STAT3 was differentially activated by IL-6 in IgA1-secreting cells from patients with IgA nephropathy compared with those from healthy control subjects. Specifically, IL-6 induced enhanced and prolonged phosphorylation of STAT3 in the cells from patients with IgA nephropathy, which resulted in overproduction of galactose-deficient IgA1. This IL-6−mediated overproduction of galactose-deficient IgA1 could be blocked by small molecule inhibitors of JAK/STAT signaling.

Discussion

Our results revealed that IL-6−induced aberrant activation of STAT3-mediated overproduction of galactose-deficient IgA1. STAT3 signaling pathway may thus represent a new target for disease-specific therapy of IgA nephropathy.

Temporal and Demographic Trends in Glomerular Disease Epidemiology in the Southeastern United States, 1986-2015

BACKGROUND AND OBJECTIVES

Large-scale, contemporary studies exploring glomerular disease epidemiology in the United States are lacking. We aimed to determine 30-year temporal and demographic trends in renal biopsy glomerular disease diagnosis frequencies in the southeastern United States.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this cross-sectional, observational study, we identified all patients with a native kidney biopsy specimen showing one of 18 widely recognized glomerular disease diagnoses referred to the University of North Carolina Chapel Hill Division of Nephropathology between 1986 and 2015. Biopsy era (1986-1995, 1996-2005, and 2006-2015) and demographics (age, sex, and race) were our primary and secondary predictors, respectively, and the relative frequency of each glomerular disease diagnosis was our primary outcome.

RESULTS

Among 21,374 patients (mean age =48.3±18.3 years old; 50.8% men; 56.8% white; 38.3% black; 2.8% Latino; 1.4% Asian; 0.8% other), the frequency of diabetic glomerulosclerosis in renal biopsy specimens increased dramatically over the three decades (5.5%, 11.4%, and 19.1% of diagnoses, respectively; P for trend <0.001). The frequency of FSGS initially increased but then declined (22.6%, 27.2%, and 24.7%, respectively; P for trend =0.64). The frequencies of other common glomerular disease subtypes remained stable (IgA nephropathy and ANCA/pauci-immune GN) or declined (minimal change disease, membranous nephropathy, membranoproliferative GN, and lupus nephritis). These temporal trends were largely preserved within all demographic subgroups, although cross-sectional frequency distributions differed according to age, sex, and race.

CONCLUSIONS

We identified significant changes in relative renal biopsy frequencies of many glomerular disease subtypes over three decades. Temporal trends were consistently observed within all major demographic groups, although relative predominance of individual glomerular disease subtypes differed according to patient age, sex, and race. We propose that exploration of behavioral and environmental exposures that likely underlie these findings should be the focus of future hypothesis-driven research.

The Survival of Roma Minority Patients on Chronic Hemodialysis Therapy - A Romanian Multicenter Survey

OBJECTIVE

The Roma minority represents the largest ethnic group in Central and South-East European countries. Data regarding the mortality in Roma hemodialysis subjects are limited. We evaluated the 3 year mortality of ESRD Roma patients treated with hemodialysis (HD).

STUDY DESIGN AND SETTING

Our prospective cohort study included 600 ESRD patients on HD therapy recruited from 7 HD centers, from the main geographical regions of Romania. The median age of the patients was 56 (19) years, 332 (55.3%) being males, 51 (8.5%) having Roma ethnicity.

RESULTS

Roma ESRD patients initiate dialysis at a younger age, 47.8 years vs. 52.3 years (P = 0.017), present higher serum albumin (P = 0.013) and higher serum phosphate levels (P = 0.021). In the Roma group, the overall 3 year mortality was higher when compared to Caucasians (33.3% vs. 24.8%). The multivariate survival analysis revealed that being of Roma ethnicity is an independent risk factor for mortality (HR = 1.74; 95% CI = 1.04-2.91; P = 0.035).

CONCLUSIONS

Roma patients with ESRD initiate HD therapy at a younger age as compared to Caucasians. They have a higher 3 year mortality rate and are dying at a younger age. Roma ethnicity represents an independent risk factor for mortality in our cohort.

Increasing frequency of idiopathic membranous nephropathy in primary glomerular disease: a 10-year renal biopsy study from a single Chinese nephrology centre

AIM

To investigate the changing of idiopathic membranous nephropathy (iMN) in China.

METHODS

This study retrospectively analyzed renal disease spectrum of 6049 patients who underwent renal biopsy at Peking University First Hospital from January 2003 to December 2012. The patients were grouped into two periods at a 5-year interval: 2003-2007 (period 1) and 2008-2012 (period 2).

RESULTS

Among 6049 renal biopsied patients, 3831 (63.3%) patients were diagnosed as primary glomerular disease (PGD). The proportion of nephrotic syndrome (NS) in PGD was significantly higher in period 2 than that in period 1 (1016/2214 [55.0%] vs 682/1617 [42.2%], P = 0.022). The proportion of iMN in PGD increased from 16.8% (217/1617) in period 1 to 29.35% (646/2214) in period 2 in all groups of age (P < 0.001). There was no significant difference of clinical characteristics including age, gender, hypertension, serum cholesterol and proteinuria between the two periods (P > 0.05). However, in young patients with iMN (14-44 years old), the percentage of renal histopathology stage I and stage II of iMN in PGDs was significantly higher in period 2 than that in period 1 (101/1240 [8.15%] vs 210/1340 [15.7%], P < 0.001).

CONCLUSION

Our study suggests that the frequency of iMN in PGD in our referral diagnostic centre has doubled over the past 10 years. The increase of adult iMN is mainly due to the increase of early stages of iMN in young patients.

Expression of human T cell immunoglobulin domain and mucin-3 on kidney tissue from immunoglobulin A nephropathy patients

The aim of this study was to evaluate the expression of human T cell immunoglobulin domain and mucin-3 (Tim-3) in renal tissue from patients with immunoglobulin A nephropathy (IgAN) and without IgAN and to evaluate the difference in Tim-3 expression between them. A total of 71 patients with IgAN as IgA group and 13 patients without IgAN as control group were enrolled in the present study. Patients in IgAN accepted percutaneous renal biopsy. We examined the expression of Tim-3 in renal tissue and the serological parameters in serum from all enrolled cases. The expression of Tim-3 and serological parameters were compared between the different groups. Positive staining of Tim-3 protein was seen in 94.3 % patients with IgAN (67 out of 71), but only 15.4 % (2 out of 13) in the cases without IgAN were positive staining of Tim-3. There were significant differences between two groups in almost all serological markers, which reflect IgAN activity. There was a nearly positive correlation between pathological manifestations and expression degree of Tim-3. High immuno-reactivity of Tim-3 was found to be significantly correlated with serological grade (p < 0.001) in IgA group, but there was no such phenomenon in control group. The results showed that there was the expression of Tim-3 in renal tissue from the patients with IgAN, but rarely expression in cases without IgAN. Expression of Tim-3 was associated with the diseases' activity.

The role of the immune system in idiopathic nephrotic syndrome: a review of clinical and experimental studies

Idiopathic nephrotic syndrome (INS) is a multifactorial disease, characterized by proteinuria, hypoalbuminemia, edema and hyperlipidemia. Studies in humans and animal models have associated INS with changes in the immune response. The purpose of this article is to review clinical and experimental findings showing the involvement of the immune response in the pathogenesis of INS. The role of the immune system in INS has been shown by clinical and experimental studies. However, the pattern of immune response in patients with INS is still not clearly defined. Many studies show changes in the dynamics of T lymphocytes, especially the regulatory T cells. Alternatively, there are other reports regarding the involvement of the complement system and B lymphocytes in the pathophysiology of INS. Indeed, none of the immunological biomarkers evaluated were undeniably linked to changes in glomerular permeability and proteinuria. On the other hand, some studies suggest a link between urinary chemokines, such as IL-8/CXCL8 and MCP-1/CCL2, and changes in glomerular permeability and/or the deterioration of glomerulopathies. To understand the pathophysiology of INS, longitudinal studies are clearly needed. The characterization of the profile of the immune response might help the development of specific and individualized therapies, leading to clinical improvement and better prognosis.

Role of basophils in the pathogenesis of minimal change nephrotic syndrome: A literature review

A number of studies have verified that minimal change nephrotic syndrome (MCNS) may result from the dysfunction of T cells and B cells, although the precise mechanisms are yet to be elucidated. It is widely recognized that MCNS is a T helper (Th)2-dominant glomerular disease caused by an imbalanced Th1/Th2 immune response. Increased levels of the Th2 cytokines, interleukin (IL)-4 and IL-13, have been demonstrated to be closely associated with disease activity. In addition, basophils can affect the Th1/Th2 balance by enhancing the Th2 response and impairing the Th1 response, which are then involved in the development of numerous diseases. However, whether basophils are vital in the pathogenesis of MCNS remains unknown. Frequent positivity of the human basophil degranulation test in patients with MCNS has been observed. Thus, basophils should be analyzed in order to determine their role in the pathogenesis of MCNS.

Relationship between hypertension, diabetes and proteinuria in rural and urban households in Yemen

Little information is available on the meanings of proteinuria in low-resource settings. A population-based, cross-sectional survey was performed in Yemen on 10 242 subjects aged 15-69 years, stratified by age, gender and urban/rural residency. Hypertension is defined as systolic blood pressure (BP) of 140 mm Hg and/or diastolic BP of 90 mm Hg, and/or self-reported use of antihypertensive drugs; diabetes is diagnosed as fasting glucose of 126 mg dl(-1) or self-reported use of hypoglycaemic medications; proteinuria is defined as +1 at dipstick urinalysis. Odds ratios (ORs) for associations were determined by multivariable logistic regression models. Prevalence (weighted to the Yemen population aged 15-69 years) of hypertension, diabetes and proteinuria were 7.5, 3.7 and 5.1% in urban, and 7.8, 2.6 and 7.3% in rural locations, respectively. Proteinuria and hypertension were more prevalent among rural dwellers (adjusted ORs 1.56; 95% confidence limit (Cl) 1.31-1.86, and 1.23; 1.08-1.41, respectively), diabetes being less prevalent in rural areas (0.70; 0.58-0.85). Differently from hypertension and diabetes, proteinuria was inversely related with age. Most importantly, 4.6 and 6.1% of urban and rural dwellers, respectively, had proteinuria in the absence of hypertension and diabetes. The approach of considering kidney damage as a consequence of hypertension and diabetes might limit the effectiveness of prevention strategies in low-income countries.

Burden of chronic kidney disease: North Africa

North Africa (NAF) is composed of six countries located in the African Sahara, namely the Western Sahara, Morocco, Algeria, Tunisia, Libya, and Egypt. Common features between these countries include similar climate, ecology, population genetics, and the socioeconomic environment. This commonality reflects on the chronic kidney disease (CKD) profile in these countries. While there are some estimates on the epidemiology of end-stage kidney disease, that of earlier stages is unknown. Several national screening programs are currently addressing this issue, such as the EGIPT-CKD project in Egypt and the MAREMAR study in Morocco. Preliminary results from the former suggest a prevalence of proteinuria in 10.6% of the relatives of patients on regular dialysis treatment. Despite the lack of reliable registries, it was possible to gather information on the etiology of CKD by direct contact with leading nephrologists in those countries. It turns out that glomerulonephritis (GN) accounts for 9–20%, diabetes 11–18%, hypertensive nephrosclerosis 10–35%, chronic interstitial nephritis 7–17%, and polycystic disease 2–3%. Compared to two decades earlier, diabetes has become more common at the expense of GN, proliferative GN, and amyloidosis regressed in favor of IgA and membranous nephropathies in Tunisian adults. Conventional schistosomal nephropathies are regressing in favor of hepatitis C viral (HCV) nephropathy in Egyptians. Focal segmental glomerulosclerosis is increasing at the expense of proliferative GNs in the region at large. Access to regular dialysis has been optimized during the past decade, with favorable outcomes despite the high incidence of HCV infection, tuberculosis, and protein-calorie malnutrition. Kidney transplantation is available in all NAF countries except the Western Sahara. About 650 transplants are performed annually from live donors, the majority in Egypt, where data from the largest center in Mansoura display a 10-year graft survival of 62%. Many transplants are performed from living unrelated donors, particularly in Egypt, which creates an ethical debate. Legislation for deceased-donor transplantation has been passed successively over the past two decades in Tunisia, Morocco, Algeria, and Egypt, which is expected to reflect quantitatively and qualitatively on the transplantation activity in the near future.

The science of early life toxic stress for pediatric practice and advocacy

Young children who experience toxic stress are at high risk for a number of health outcomes in adulthood, including cardiovascular disease, cancers, asthma, and depression. The American Academy of Pediatrics has recently called on pediatricians, informed by research from molecular biology, genomics, immunology, and neuroscience, to become leaders in science-based strategies to build strong foundations for children's life-long health. In this report, we provide an overview of the science of toxic stress. We summarize the development of the neuroendocrine-immune network, how its function is altered by early life adversity, and how these alterations then increase vulnerability to disease. The fact that early environments shape and calibrate the functioning of biological systems very early in life is both a cautionary tale about overlooking critical periods in development and reason for optimism about the promise of intervention. Even in the most extreme cases of adversity, well-timed changes to children's environments can improve outcomes. Pediatricians are in a unique position to contribute to the public discourse on health and social welfare by explaining how factors that seem distal to child health may be the key to some of the most intractable public health problems of our generation. We consider the challenges and opportunities for preventing toxic stress in the context of contemporary pediatric practice.

The clinical characteristics of steroid responsive nephrotic syndrome of children according to the serum immunoglobulin E levels and cytokines

PURPOSE

The nephrotic syndrome (NS) is characterized by the favorable response to glucocorticoid therapy and the development of NS may be associated with dysfunctional immune systems. In order to investigate the serum immunoglobulin E (IgE) levels and cytokines activity in pediatric NS, the total of 32 steroid responsive NS patients and 5 healthy controls were enrolled in this study.

MATERIALS AND METHODS

All patients were divided into two groups according to the initial serum IgE levels, such as normal and high IgE group, and their clinical characteristics were evaluated. In addition, serum levels of interleukin (IL)-4, IL-5, IL-10 and transforming growth factor (TGF)-β were compared and correlated with serum albumin, proteinuria by means of disease severity, and cytokines.

RESULTS

In the high IgE group, the higher comorbidity of allergic diseases and relapsing rate, the longer duration of steroid therapy before initial remission, and the higher serum IL-4 and IL-5 levels were found. In all patients, initially higher serum levels of IL-4 and IL-5 declined to normal levels after steroid therapy, whereas the serum IL-10 levels showed no significant difference between nephrotic phase (heavy proteinuria) and remission phase (no proteinuria) of NS. The serum TGF-β levels of the nephrotic phase were significantly lower than those of remission phase or control group, and returned to normal control levels after steroid therapy.

CONCLUSION

This study indicates that initial IgE level is associated with steroid responsiveness and disease severity, and cytokine activities may also be related to the pathogenesis of pediatric steroid responsive NS.

End-stage renal disease among Roma and non-Roma: Roma are at risk

OBJECTIVES

Ethnic differences in the occurrence of end-stage renal disease (ESRD) are reported on various populations across the world, but evidence on Roma is lacking. The aim of this study was to explore the relative risk (RR) of ESRD for Roma who constitute a major minority in Slovakia.

METHODS

Patients treated by means of hemodialysis during 2005-2008 were questioned for their ethnicity. Rates of ESRD among Roma and non-Roma based on hemodialysis data were calculated as well as the RR of Roma for ESRD. The latter was repeated after standardization for differences in age of both populations.

RESULTS

Roma represented 11.6 % of all hemodialyzed patients. The RR of ESRD for Roma was 1.34, compared to the majority population. After age standardization, the RR for Roma was 2.85.

CONCLUSION

This study shows that the risk for ESRD is significantly higher for Roma than for non-Roma. A genetic propensity of Roma to renal failure may partially explain the higher risk. Moreover, a poorer control of risk factors for ESRD in Slovak Roma contributes to the increased risk.

Adipose-derived stem cells improve renal function in a mouse model of IgA nephropathy

T-cell dysregulation plays an important role in the pathogenesis of immunoglobulin A nephropathy (IgAN). Adipose-derived stem cells (ASCs) have been reported to be able to prevent tissue damage through immune-modulating effects. To evaluate the effects of ASCs in high IgA ddY (HIGA) mice, ASCs were isolated from HIGA mice with different stages of IgAN before and after disease onset. ASCs were injected at a dose of 5×10(6) cells/kg body weight through the tail vein every 2 weeks for 3 months. Although the administered ASCs were rarely detected in the glomeruli, 24-h proteinuria was markedly decreased in all ASC-treated groups. Although glomerular deposition of IgA was not significantly different among groups, mesangial proliferation and glomerulosclerosis were dramatically decreased in most ASC treatment groups. In addition, levels of fibrotic and inflammatory molecules were markedly decreased by ASC treatment. Interestingly, ASC therapy significantly decreased Th1 cytokine activity in the kidney and caused a shift to Th2 responses in spleen T-cells as determined by FACS analysis. Furthermore, conditioned media from ASCs abrogated aggregated IgA-induced Th1 cytokine production in cultured HIGA mesangial cells. These results suggest that the beneficial effects of ASC treatment in IgAN occur via paracrine mechanisms that modulate the Th1/Th2 cytokine balance. ASCs are therefore a promising new therapeutic agent for the treatment of IgAN.

Th17/Treg imbalance in adult patients with minimal change nephrotic syndrome

To determine whether Th17/Treg balance was abnormal in adult patients with minimal change nephrotic syndrome (MCNS), we studied 25 patients with new-onset MCNS and 20 normal persons. The results showed that MCNS patients exhibited a significant increase in Th17 number, Th17-related cytokines (IL-17 and IL-23), and transcription factor (RORγt) levels, as well as an obvious decrease in Treg number, Treg-related cytokines (TGF-β1 and IL-10), and transcription factor (Foxp3) levels. The Th17/Treg ratios increased along with increased proteinuria and decreased albumin levels in patients with MCNS. IL-17 protein expression was also detected in the renal biopsy tissue of MCNS patients, particularly in patients with acute renal failure. Further, Th17/Treg balance returned to normal after effective corticosteroids therapy in 16 MCNS patients. These results indicated that Th17/Treg imbalance existed in MCNS patients, suggesting a potential role of Th17/Treg imbalance in the pathogenesis of MCNS.

The incidence of primary glomerulonephritis worldwide: a systematic review of the literature

BACKGROUND

Little is known about the worldwide variation in incidence of primary glomerulonephritis (GN). The objective of this review was to critically appraise studies of incidence published in 1980-2010 so that an overall view of trends of these diseases can be found. This would provide important information for determining changes in rates and understanding variations between countries.

METHODS

All relevant papers found through searches of Medline, Embase and ScienceDirect were critically appraised and an assessment was made of the reliability of the reported incidence data.

RESULTS

This review includes 40 studies of incidence of primary GN from Europe, North and South America, Canada, Australasia and the Middle East. Rates for the individual types of disease were found to be in adults, 0.2/100,000/year for membrano-proliferative GN, 0.2/100,000/year for mesangio-proliferative GN, 0.6/100,000/year for minimal change disease, 0.8/100,000/year for focal segmental glomerulosclerosis, 1.2/100,000/year for membranous nephropathy and 2.5/100,000/year for IgA nephropathy. Rates were lower in children at around 0.1/100,000/year with the exception of minimal change disease where incidence was reported to be 2.0/100,000/year in Caucasian children with higher rates in Arabian children (9.2/100,000/year) and Asian children (6.2-15.6/100,000/year).

CONCLUSIONS

This study found that incidence rates of primary GN vary between 0.2/100,000/year and 2.5/100,000/year. The incidence of IgA nephropathy is at least 2.5/100,000/year in adults; this disease can exist subclinically and is therefore only detected by chance in some patients. In addition, referral policies for diagnostic biopsy vary between countries. This will affect the incidence rates found.

Down-regulation of core 1 beta1,3-galactosyltransferase and Cosmc by Th2 cytokine alters O-glycosylation of IgA1

Background. Patients with IgA nephropathy (IgAN) have an increased amount of abnormally O-glycosylated IgA1 in circulation, in glomerular deposits and produced by tissue cells in vitro. Although increased production of Th2 cytokines by peripheral blood lymphocytes and a functional abnormality of core 1 β1,3-galactosyltransferase (C1β3Gal-T) have been proposed as mechanisms underlying pathogenesis of IgAN, they are still obscure and are not connected.

Methods. To clarify the effect of T-cell cytokines, we analysed the mRNA levels of C1β3Gal-T and its molecular chaperone Cosmc, C1β3Gal-T activity and subsequent O-glycosylation of IgA1 in a human B-cell line stimulated with these cytokines. The surface IgA1-positive human B-cell line was cultured with recombinant human IFN-γ, IL-2, IL-4 or IL-5. The production and glycosylation of IgA1 were determined by sandwich ELISA and enzyme-linked lectin binding assay, respectively. The mRNA levels of C1β3Gal-T and Cosmc were quantitatively measured by real-time PCR. C1β3Gal-T activity was analysed using high-performance liquid chromatography.

Results. IgA1 production by IL-4-stimulated cells was significantly higher than controls or after IFN-γ or IL-5. The terminal glycosylation of secreted IgA1 was altered in response to IL-4. IL-4 stimulation significantly decreased the mRNA levels of both C1β3Gal-T and Cosmc and of C1β3Gal-T activity. IL-4 stimulation was clearly blocked by recombinant human IL-4 soluble receptor.

Conclusions. It appears that Th2 cytokine IL-4 may play a key role in controlling glycosylation of the IgA1 hinge region.

Ascaris lumbricoides-induced suppression of total and specific IgE responses in atopic subjects is interleukin 10-independent and associated with an increase of CD25(+) cells

Ascaris presence in humans has been associated with high levels of blood eosinophils and serum IgE. This study was designed to address the influence of Ascaris infection on allergic and inflammatory parameters of atopic subjects. A cross-sectional design was used, and atopic individuals to be assessed were divided into 3 groups including Ascaris-infected, anti-Ascaris IgG-positive (seropositive), and control subjects. All subjects enrolled had positive skin test reactivity to at least 1 perennial or seasonal allergen; however, levels of C-reactive protein, C3, and C4 were within normal range values. Eosinophil percentage was not significantly different among the groups studied. Total IgE and specific anti-Ascaris IgE levels in the seropositive group were significantly higher than concentrations found in both control and infected groups. Interleukin (IL)-4 release in Ascaris-infected patients was significantly increased versus seropositives, who were able to produce more IL-4 than controls. The levels of IL-10 were lower in the seropositives as well as infected subjects in comparison with controls. CD25(+) lymphocyte populations were significantly increased in the infected group versus the seropositives as well as the controls. Lung function tests of some selected seropositive subjects were significantly impaired. The same parameters of a representative infected patient were not different from controls. Our data on T helper type 2 cells (Th2) and regulatory T cells (Treg) features, as well as CD25(+) lymphocyte increase, suggest an Ascaris-induced mechanism leading to parasite survival. Moreover, the stable control of both T helper type 1 cells (Th1) and Th2 immunity cascades, paralleled by the absence of overwhelming inflammatory systemic reactions and lack of allergic syndromes, may result in a favorable host condition.

Potential immunopathogenic role of the mucosa-bone marrow axis in IgA nephropathy: insights from animal models

Impaired immune regulation along the mucosa-bone marrow axis has been postulated to play an important role in the pathogenesis of IgA nephropathy. Animal models have allowed us to study such changes in detail. Accumulating evidence from a number of animal models suggest that there is dysregulation of innate and cellular immunity in IgA nephropathy, resulting in changes to the mucosal immune system. These changes appear to be linked closely to a disruption of mucosal tolerance, resulting in the abnormal priming and dissemination of cells to sites such as the bone marrow where they are responsible for the synthesis of nephritogenic IgA. These findings suggest that future treatment strategies should focus on manipulating the priming and dissemination of these memory cells to prevent the appearance of nephritogenic IgA in the systemic compartment.

Th1 polarization in murine IgA nephropathy directed by bone marrow-derived cells

IgA nephropathy is the most common form of progressive glomerulonephritis although the pathophysiology of this nephropathy is unclear. The ddY mouse is a spontaneous animal model with variable incidence and extent of glomerular injury mimicking human IgA nephropathy. Here, we transplanted bone marrow cells from 20-week-old ddY mice with beginning or quiescent IgA nephropathy into irradiated similar ddY mice, C57Bl/6 (Th1 prone) mice, or BALB/c (Th2 prone) mice. Serum IgA/IgG complex and Th1/Th2 polarization of spleen cells was determined by enzyme-linked immunosorbent assay and confirmed by fluorescent cytometric analysis. The ddY mice with commencing IgA nephropathy demonstrated strong polarization toward Th1, while those with quiescent disease were Th2 polarized. Serum levels of IgA/IgG2a immune complex significantly correlated with the severity of the glomerular lesions. Bone marrow taken from mice with commencing IgA nephropathy conferred IgA nephropathy with Th1 polarization in recipient-quiescent mice, while transplantation from the quiescent mice ablated glomerular injury and mesangial IgA/IgG deposition in those commencing IgA disease. However, adoptive transfer of CD4(+) T cells from those whose disease began failed to induce any IgA deposition or renal injury. Our study suggests that bone marrow cells, presuming IgA producing cells, may initiate this disease. Th1 cells may be involved in the pathophysiology of the disease after glomerular IgA deposition.

Coincident activation of Th2 T cells with onset of the disease and differential expression of GRO-gamma in peripheral blood leukocytes in minimal change disease

BACKGROUND

Involvement of Th2 T cells/NFkappaB in minimal change disease (MCD) has been postulated. A promising but unconfirmed glomerular permeability factor (GPF) from MCD T cells has been described. We explored whether GPF was the consequence of Th2 cell activation.

METHODS

Peripheral blood leukocytes (PBL) from 16 MCD patients and 7 normal controls were analyzed and the results were statistically compared.

RESULTS

Flow cytometry demonstrated a significant expansion of CD4+ T cell population and dramatically increased CD69+ cells among CD4+ T cells in MCD, suggesting coincident activation of T cells with onset of the disease. RT-PCR on RNA from either freshly isolated PBL or post in vitroactivation showed high-level expression of the Th2 cytokine interleukin-4 in all MCD patients. Importantly, both antibody microarray assay on sera and RT-PCR on mRNA of PBL revealed expression of a CXC chemokine GRO-gamma (growth-related oncogene) in all MCD patients as compared with one of 7 controls.

CONCLUSIONS

Our results reveal an association between onset of MCD and activation of Th2 cells. The GRO family has been implicated in the function of endothelial cells, and its expression is under NFkappaB regulation. Thus, GRO-gamma is a promising candidate for Th2-associated GPF in MCD.

A case of unfulfilled expectations. Cytokines in idiopathic minimal lesion nephrotic syndrome

Idiopathic minimal lesion nephrotic syndrome (IMLNS) was proposed to be a disorder of T-cell dysfunction by Shalhoub in 1974. The mechanisms by which T-cells increase glomerular permeability have remained elusive (and unproven). There is evidence that IMLNS may be due to a circulating factor released from activated T-cells. In recent years, efforts have been made to identify this pathogenetic cytokine as well as to understand the mechanism(s) for the increased release of this factor. This review attempts to critically analyze the available published data. Using different methodologies, investigators have focused on the production of cytokines in patients with IMLNS during relapse and remission. This has resulted in a plethora of data without definitive conclusions. The pathogenetic cytokine has not been identified, and it is questionable whether there is a Th2 dominance in IMLNS. The review of the available data illustrates the difficulties encountered when one is studying the cytokine secretory pattern in patients with IMLNS. Differences in patient population, type of cells studies, sample preservation, and methodology used to measure cytokines are some of the factors that could account for the disparity of observed results.